build: add Spigot plugin foundation

design/user-stories/us-008-build-and-release-plugin.md

@@ -2,7 +2,7 @@
 type: User Story
 title: "US-008: Build and release the plugin"
 description: Give maintainers repeatable Spigot builds, automated verification, and versioned Gitea releases.
-status: backlog
+status: done
 ---
 
 # US-008: Build and release the plugin
@@ -11,15 +11,15 @@ As a **plugin maintainer**, I want automated builds and releases modeled on Spig
 
 ## Acceptance criteria
 
-- [ ] The Gradle project compiles against Spigot API `26.2-R0.1-SNAPSHOT` using a Java 17 toolchain.
-- [ ] Compiler lint warnings fail the build.
-- [ ] Automated JUnit 5 tests run as part of the Gradle check lifecycle.
-- [ ] Pushes and pull requests build and test the plugin in Gitea Actions.
-- [ ] Pull requests validate conventional commit messages.
-- [ ] CI stores a development JAR as a workflow artifact.
-- [ ] Main-branch conventional commits drive semantic versioning.
-- [ ] A successful release builds a versioned JAR and attaches it to the corresponding Gitea release.
-- [ ] Build files, Gradle wrapper, workflows, and release behavior follow `../spigot-base/` where applicable while using Spigot Harvest names and identifiers.
+- [x] The Gradle project compiles against Spigot API `26.2-R0.1-SNAPSHOT` using a Java 17 toolchain.
+- [x] Compiler lint warnings fail the build.
+- [x] Automated JUnit 5 tests run as part of the Gradle check lifecycle.
+- [x] Pushes and pull requests build and test the plugin in Gitea Actions.
+- [x] Pull requests validate conventional commit messages.
+- [x] CI stores a development JAR as a workflow artifact.
+- [x] Main-branch conventional commits drive semantic versioning.
+- [x] A successful release builds a versioned JAR and attaches it to the corresponding Gitea release.
+- [x] Build files, Gradle wrapper, workflows, and release behavior follow `../spigot-base/` where applicable while using Spigot Harvest names and identifiers.
 
 ## Related